This invention relates to pitch change mechanism for a propulsor and particularly to an improved pitch change actuator of the harmonic drive type.
U.S. patent application Ser. No. 334,334 filed on Feb. 21, 1973 by Merritt Andrews, now U.S. Pat. No. 3,893,789 and assigned to the same assignee discloses and describes a harmonic pitch change actuator and is incorporated herein by reference. As disclosed therein, it is customary to utilize the rigid spline and through a bevel gear arrangement rotate the blade about its longitudinal axis. It is also customary to ground the flexispline to a ground or the barrel.
I have found that I can double the torque of the pitch change actuation by coupling the flexispline to the root of the blade and utilize its force as a part of the harmonic drive actuator. This will result in obtaining the same output of a harmonic drive that is substantially half the size as the heretofore actuator.